Cutter-bit assemblies of various designs are widely used in mining and tunnelling operations. Normally, such assemblies are composed of a holder secured to a cutting appliance or machine, such as a coal plough, and a separate cutter-bit which is inserted into a pocket in the holder. To secure the cutter-bit within the holder it is known to employ a locking element which jams a shank of the cutter-bit in the pocket. U.S. Pat. No. 4,456,307 describes an assembly which uses an arcuate wedge as the locking element. To secure the wedge in position a deformable lug or tab can be bent around a front wall of the pocket. During use of the assembly, however, especially when the assembly is subject to impact stress, deformation and wear can cause the loosening of the wedge and the cutter-bit and chattering and damage can then occur.
The service life of the cutter-bits can be improved significantly if the means used to secure the cutter-bits in the holders is made more reliable. With this in mind the present invention seeks to provide improve cutter-bit assemblies.